[FEAT_REQ] Add Dark Mode Toggle Button to Header

[tomonarifeehan]

Is your feature request related to a problem? Please describe.
Currently, the application’s dark mode relies solely on the system settings of the user's computer. This approach lacks flexibility, as users must change their entire system theme to adjust the application’s appearance. This is inconvenient for users who may want to keep their system in light mode while using the application in dark mode or vice versa. This limitation hinders quick adjustments and reduces the overall usability and customization of the interface.

Describe the solution you'd like
Introduce a dedicated Dark Mode toggle button within the web applications header, allowing users to manually switch between light and dark themes regardless of the system settings. The toggle should give users the autonomy to choose their preferred theme directly within the app, providing immediate feedback and preserving the selected theme across sessions.

Describe alternatives you've considered

• Keeping the current system-reliant setting as an option, with an additional toggle for manual control, allowing users to override the system setting only within the application.
• Offering a "match system theme" option alongside the manual toggle, giving users the choice to let the app automatically adapt to system settings or manage the theme independently.

Additional context
The addition of a Dark Mode toggle will enhance user control, offering a more personalized and adaptable user experience. Below are some examples from other applications that have successfully implemented an in-app toggle for Dark Mode, allowing independent theme selection.